@book { DieSprachverbreitungspolitikderDDR,
    title = "Die Sprachverbreitungspolitik der DDR",
    author = "Martin {Praxenthaler}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1093611"
}